Investigation of indoor environment and thermal comfort of building installed with bifacial PV modules

•The building integrated with bifacial PV modules was established.•The indoor environment and comfort of the PV building were studied.•An optimization design of the PV building was put forward to improve the indoor environment. In comparison with common PV module, bifacial PV module can increase energy output by installing cells on both sides of the module. Due to the thermoelectric effect in the rear, the impact of bifacial PV module on indoor environment is more complex. To study indoor environment of bifacial PV module as building envelope, a building integrated bifacial PV module was established. Through the experiments and simulation of the PV building, it is found that thermal stratification is obvious at noon in summer, which indicates the bifacial PV module causes a large influence on the indoor temperature. PMV is between -1 and +1 in summer nights and winter days but it becomes poor in sunny days due to the large solar radiation intensity. Additionally, the indoor light environment is studied. The indoor lighting is ideal in general but overlarge when the solar radiation is too strong. For the purpose of improving the indoor comfort, the coverage of PV module was changed and the heat insulation reflective layer was installed behind the PV modules. With the optimization design, the indoor environment has been significantly improved, and the period of annual thermal comfort has increased by 8%.